Fix semantics of mu_attribute_to_string

* include/mailutils/attribute.h (MU_STATUS_BUF_SIZE): New define.
* libproto/mbox/mbox.c: Update use of mu_attribute_to_string.
* mailbox/amd.c: Likewise.
* mailbox/attribute.c (mu_string_to_flags): Rewrite.
(mu_attribute_to_string): Fill the string with flag letters only, without
"Status:" prefix and final newline.
* NEWS: Update.

-GNU mailutils NEWS -- history of user-visible changes. 2009-03-03
+GNU mailutils NEWS -- history of user-visible changes. 2009-03-04
 Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 
 2008, 2009 Free Software Foundation, Inc.
 See the end of file for copying conditions.
@@ -22,7 +22,7 @@ All MU client utilities make use of the user ticket file,
 
 ** Changed functions
 
-- mu_message_save_to_mailbox: removed `ticket' argument.
+*** mu_message_save_to_mailbox: removed `ticket' argument.
 
 New prototype is:
 
@@ -30,7 +30,11 @@ int mu_message_save_to_mailbox (mu_message_t msg,
                                 mu_debug_t debug,
 				const char *toname,
 				int perms);
-				       
+
+*** mu_attribute_to_string
+
+This function now returns a string consisting of flag letters only, without
+"Status:" prefix or final newline.
 
 
 Version 2.0:

 /* GNU Mailutils -- a suite of utilities for electronic mail
-   Copyright (C) 1999, 2000, 2001, 2005, 2007 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2000, 2001, 2005, 2007,
+   2009 Free Software Foundation, Inc.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -96,6 +97,9 @@ extern int mu_attribute_is_equal        (mu_attribute_t, mu_attribute_t att2);
 
 extern int mu_attribute_copy            (mu_attribute_t, mu_attribute_t);
 
+/* Maximum size of buffer for mu_attribute_to_string call, including nul */
+#define MU_STATUS_BUF_SIZE sizeof("OAFRd")
+  
 extern int mu_attribute_to_string       (mu_attribute_t, char *, size_t, size_t *);
 extern int mu_string_to_flags           (const char *, int *);
 

@@ -1585,14 +1585,19 @@ mbox_append_message0 (mu_mailbox_t mailbox, mu_message_t msg, mu_off_t *psize,
       case MBOX_STATE_APPEND_ATTRIBUTE:
       /* Put the new attributes.  */
       {
-	char abuf[64];
+#define STATUS_PREFIX_LEN (sizeof(MU_HEADER_STATUS) - 1 + 2)
+	char abuf[STATUS_PREFIX_LEN + MU_STATUS_BUF_SIZE + 1];
 	size_t na = 0;
 	mu_attribute_t attr = NULL;
-	abuf[0] = '\0';
-	mu_message_get_attribute (msg, &attr);
-	mu_attribute_to_string (attr, abuf, sizeof(abuf), &na);
 
-	status = mu_stream_write (mailbox->stream, abuf, na, *psize, &n);
+	strcpy(abuf, MU_HEADER_STATUS);
+	strcat(abuf, ": ");
+	mu_message_get_attribute (msg, &attr);
+	mu_attribute_to_string (attr, abuf + STATUS_PREFIX_LEN, 
+	                        sizeof(abuf) - STATUS_PREFIX_LEN - 1, &na);
+	strcat (abuf, "\n");
+	na = strlen (abuf);
+	mu_stream_write (mailbox->stream, abuf, na, *psize, &n);
 	if (status != 0)
 	  break;
 	*psize += n;

 /* GNU Mailutils -- a suite of utilities for electronic mail
    Copyright (C) 1999, 2000, 2001, 2002, 2003, 
-   2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+   2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -613,7 +613,8 @@ _amd_message_save (struct _amd_data *amd, struct _amd_message *mhm,
   mu_body_t body;
   const char *sbuf;
   mu_envelope_t env = NULL;
-  
+  char statbuf[MU_STATUS_BUF_SIZE];
+
   status = mu_message_size (msg, &bsize);
   if (status)
     return status;
@@ -661,7 +662,7 @@ _amd_message_save (struct _amd_data *amd, struct _amd_message *mhm,
   while ((status = mu_stream_readline (stream, buf, bsize, off, &n)) == 0
 	 && n != 0)
     {
-      if (_amd_delim(buf))
+      if (_amd_delim (buf))
 	break;
 
       if (!(strncasecmp (buf, "status:", 7) == 0
@@ -710,10 +711,10 @@ _amd_message_save (struct _amd_data *amd, struct _amd_message *mhm,
   
   /* Add status */
   mu_message_get_attribute (msg, &attr);
-  mu_attribute_to_string (attr, buf, bsize, &n);
+  mu_attribute_to_string (attr, statbuf, sizeof (statbuf), &n);
   if (n)
     {
-      nbytes += fprintf (fp, "%s", buf);
+      nbytes += fprintf (fp, "Status: %s\n", statbuf);
       nlines++;
     }
   nbytes += fprintf (fp, "\n");

 /* GNU Mailutils -- a suite of utilities for electronic mail
    Copyright (C) 1999, 2000, 2001, 2004, 2005, 
-   2007 Free Software Foundation, Inc.
+   2007, 2009 Free Software Foundation, Inc.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -31,10 +31,9 @@
 #endif
 
 #include <mailutils/errno.h>
+#include <mailutils/mutil.h>
 #include <attribute0.h>
 
-static int flags_to_string (int, char *, size_t, size_t *);
-
 int
 mu_attribute_create (mu_attribute_t *pattr, void *owner)
 {
@@ -384,6 +383,31 @@ mu_attribute_copy (mu_attribute_t dest, mu_attribute_t src)
   return 0;
 }
 
+struct flagtrans
+{
+  int flag;
+  char letter;
+};
+
+/* The two macros below are taken from gnulib module verify.h */
+#define mu_verify_true(R) \
+  (!!sizeof \
+   (struct { unsigned int verify_error_if_negative_size__: (R) ? 1 : -1; }))
+#define mu_verify(R) extern int (* verify_function__ (void)) [mu_verify_true (R)]
+
+static struct flagtrans flagtrans[] = {
+  { MU_ATTRIBUTE_SEEN, 'O' },
+  { MU_ATTRIBUTE_ANSWERED, 'A' },
+  { MU_ATTRIBUTE_FLAGGED, 'F' },
+  { MU_ATTRIBUTE_READ, 'R' },
+  { MU_ATTRIBUTE_DELETED, 'd' },
+  { 0 }
+};
+
+/* If cc reports an error in this statement, fix the MU_STATUS_BUF_SIZE
+   declaration in include/mailutils/attribute.h */
+mu_verify (MU_ARRAY_SIZE (flagtrans) == MU_STATUS_BUF_SIZE);
+
 int
 mu_string_to_flags (const char *buffer, int *pflags)
 {
@@ -401,64 +425,43 @@ mu_string_to_flags (const char *buffer, int *pflags)
   else
     sep = buffer;
 
-  while (*sep)
+  for (; *sep; sep++)
     {
-      if (strchr (sep, 'R') != NULL || strchr (sep, 'r') != NULL)
-	*pflags |= MU_ATTRIBUTE_READ;
-      if (strchr (sep, 'O') != NULL || strchr (sep, 'o') != NULL)
-	*pflags |= MU_ATTRIBUTE_SEEN;
-      if (strchr (sep, 'A') != NULL || strchr (sep, 'a') != NULL)
-	*pflags |= MU_ATTRIBUTE_ANSWERED;
-      if (strchr (sep, 'F') != NULL || strchr (sep, 'f') != NULL)
-	*pflags |= MU_ATTRIBUTE_FLAGGED;
-      sep++;
+      struct flagtrans *ft;
+
+      for (ft = flagtrans; ft->flag; ft++)
+	if (ft->letter == *sep)
+	  {
+	    *pflags |= ft->flag;
+	    break;
+	  }
     }
   return 0;
 }
 
+/* NOTE: When adding/removing flags, make sure to update the
+   MU_STATUS_BUF_SIZE define in include/mailutils/attribute.h */
 int
-mu_attribute_to_string (mu_attribute_t attr, char *buffer, size_t len, size_t *pn)
-{
-  int flags = 0;;
-  mu_attribute_get_flags (attr, &flags);
-  return flags_to_string (flags, buffer, len, pn);
-}
-
-static int
-flags_to_string (int flags, char *buffer, size_t len, size_t *pn)
+mu_attribute_to_string (mu_attribute_t attr, char *buffer, size_t len,
+			size_t *pn)
 {
-  char status[32];
-  char a[8];
-  size_t i;
-
-  *status = *a = '\0';
-
-  if (flags & MU_ATTRIBUTE_SEEN)
-    strcat (a, "O");
-  if (flags & MU_ATTRIBUTE_ANSWERED)
-    strcat (a, "A");
-  if (flags & MU_ATTRIBUTE_FLAGGED)
-    strcat (a, "F");
-  if (flags & MU_ATTRIBUTE_READ)
-    strcat (a, "R");
-  if (flags & MU_ATTRIBUTE_DELETED)
-    strcat (a, "d");
-
-  if (*a != '\0')
-    {
-      strcpy (status, "Status: ");
-      strcat (status, a);
-      strcat (status, "\n");
-    }
+  int flags = 0;
+  char buf[MU_STATUS_BUF_SIZE];
+  int i;
+  int rc;
+  struct flagtrans *ft;
+  
+  rc = mu_attribute_get_flags (attr, &flags);
+  if (rc)
+    return rc;
 
-  i = strlen (status);
+  i = 0;
+  for (ft = flagtrans; ft->flag; ft++)
+    if (ft->flag & flags)
+      buf[i++] = ft->letter;
+  buf[i++] = 0;
 
-  if (buffer && len != 0)
-    {
-      strncpy (buffer, status, len - 1);
-      buffer[len - 1] = '\0';
-      i = strlen (buffer);
-    }
+  i = mu_cpystr (buffer, buf, i);
   if (pn)
     *pn = i;
   return 0;